ITHACA, N.Y. -- A team of researchers at Cornell University has identified the exact year that logs were cut at an archaeological site in Turkey, a finding that has major implications for understanding the history of the Greeks, Egyptians and other ancient civilizations.
Reporting in the journal Nature (June 27), Peter I. Kuniholm, Cornell professor of the history of art and archaeology, with other researchers in the university's Aegean Dendrochronology Project and at the universities of Heidelberg and Reading, have constructed a tree-ring sequence spanning 1,503 years from the ring growth patterns preserved in wood and charcoal samples at 22 sites throughout the eastern Mediterranean. They identified this exact "window," from 2200 B.C. to 718 B.C., by analyzing variations in the width of annual tree rings (which are altered by changes in climate and moisture) from the wood and charcoal remains of ancient tombs, gates and buildings unearthed at these sites.
Using dendrochronology techniques they have perfected along with radiocarbon dating, the researchers were able to determine the exact year that some of those logs were chopped down. They report that logs used to build the inner chamber of the Midas Mound Tumulus, a massive tomb named for King Midas of the Phrygians and located at the Gordion archaeological site, were cut in 718 B.C.
"That is not plus-or-minus anything; it is a date 'to the year,'" said Cornell doctoral student Maryanne Newton, one of the Nature article's coauthors. "That level of precision, based on the fact that trees put on a single growth ring per year, is unique."
The researchers supplemented their dendrochronology work with radiocarbon "wiggle-matching," a process in which the radiocarbon profiles of the timbers are superimposed on a calibrated time scale and moved until the lines match up, and their knowledge of an earlier climatic event.